The present invention relates generally to improvements in a photographic camera employing a cartridge film and it relates more particularly to a camera which operatively accepts only a cartridge of film having a predetermined sensitivity and which cannot be inadvertently operatively loaded with a cartridge of film having a sensitivity other than said predetermined sensitivity.
There has been heretofore known a simplified photographic camera employing a cartridge film in which the photographic sensitivity of the film employable with the camera is predetermined to a given sensitivity value (for example, ASA 100) so that the mechanism for compensating for different film sensitivities which are found in the more sophisticated camera is omitted. With a camera of the above construction, the proper exposure is obtained only when the photographic film having such a predetermined sensitivity is employed. For example, in the case of a camera adapted for only ASA 100 film as above, any film may be employed ranging in sensitivity from ASA about 80 to ASA about 120, wherein compensation for overexposure or underexposure is normally provided by the film latitude. However, because of their same contour, shape and size, any of the film cartridges can be loaded into the camera, irrespective of their dissimilar sensitivities. This leads to the disadvantage that the photographer may inadvertently load the camera with a film having an incompatible or nonconforming sensitivity. In the above example, a film having a sensitivity in which compensation for overexposure or underexposure is not provided by film latitude, e.g., ASA 800 or ASA 16, would not be able to obtain the desired proper exposure.